ATP 1194PA
ATP 1194PA
(a) Location
ATP 1194PA is located in the Cooper-Eromanga Basins of SW Queensland, some 100km northwest of Quilpie and 10km north of Eromanga. It comprises 340 sub-blocks, an area of approximately 1,043 km2.
(b) Previous exploration
ATP 1194PA has been relatively under-explored when compared to the adjacent areas to the south and west The existing seismic grid comprises 2,163 line kilometres of multi-vintage 2D mostly regional seismic data of variable quality, with a more closely spaced grid over the Cumbroo anticline in the northeast of the area. Two exploration wells have been drilled within the ATP 1194PA area, both of which were P&A.
(c) Geology
ATP 1194PA offers excellent coverage of the Jurassic to Cretaceous Eromanga Basin and the Permian to Triassic Cooper Basin. The north-western part of ATP 1194PA overlies the south-eastern extension of the Ullenbury Depression and the northern extremities of the north-plunging Tallyabra anticlinal trend, along which are located to the south the Byrock oil discovery and the Bodalla South oil field. Several Permian gas discoveries located close to the north-western part of ATP 1194PA occur in small, low relief structures developed on the north-plunging Harkaway anticlinal trend. The southern part of ATP 1194PA overlies the western flank of the Tallyabra anticlinal trend, upon which is located the Bodalla South oil field.
(d) Source Rocks and Potential Reservoirs
ATP 1194PA is considered prospective for oil and gas within the Permo-Triassic Cooper Basin section, and for oil in the Jurassic and early Cretaceous Eromanga Basin sequence. A number of oil fields lie immediately to the south and east of the permit area: Bodalla South, Kenmore and Black Stump. Oil production from these fields is obtained primarily from the Jurassic Hutton Sandstone and ‘Basal Jurassic’ (Poolawanna) Formation. Two Permian gas fields, Thylungra and Bunya, lie to the west of the northern-most part of ATP 1194PA, while the Byrock Permian oil and gas discovery is enclosed by the eastern part of the permit area. Several other wells drilled near to ATP 1194PA have tested gas or recovered oil from the Permian section but were P&A at the time as non-commercial discoveries.
Coals and carbonaceous shales of Permian age are proven hydrocarbon source rocks in the Cooper Basin. The Permian section in and adjacent to ATP 1194PA is known to contain source rocks within the Toolachee and Patchawarra Formations that are mature for hydrocarbon generation and are believed to have sourced the surrounding gas-condensate fields. The northern and central part of ATP 1194PA is considered prospective for a Permian and, potentially, Triassic gas play.
The Permian reservoirs in this area exhibit variable reservoir quality, with average porosities typically less than 15% and variable DST flow rates, locally ranging up to 5.8 mmscfd (Bunya-1 Toolachee Formation). The Permian section where drilled in a number of wells in and adjacent to ATP 1194PA contains gas-charged sandstones of lower reservoir quality that provide a potential tight gas play in this area. Permian and Triassic reservoir sandstones within this area are sealed by intraformational shales. The Cooper Basin reservoir section in this area is sealed by a well-developed shaley unit within the Triassic Nappamerri Group.
Oil has been produced from the Birkhead, Hutton and Basal Jurassic (Poolowanna) Eromanga Basin reservoirs in the Bodalla South, Kenmore and Black Stump oil fields that lie adjacent to the east and south margins of ATP 1194PA. Oil shows have also been recorded from Eromanga Basin reservoirs in a number of wells drilled in close proximity to the permit. These shows highlight the potential for oil accumulations within the Eromanga Basin section in ATP 1194PA. The principal Eromanga Basin reservoirs are the Jurassic Hutton Formation and Basal Jurassic (Poolowanna) Formation, both typically exhibiting very good reservoir quality. Secondary reservoir units include sandstones within the Birkhead and Westbourne Formations. Seals are provided by the extensive shales of the Birkhead Formation and by intra-formational shales. Marine claystone of the Cretaceous Wallumbilla Formation provide an effective regional seal for the Eromanga Basin section.
Many of the Eromanga Basin oil fields are known to be sourced from Cooper Basin source rocks, with migration into the Eromanga Basin section occurring in areas where the Triassic regional seals are breached. The area of ATP 1194PA is expected to contain well developed Triassic seals, thus charge of Eromanga Basin reservoirs from a Cooper Basin source would require vertical migration of hydrocarbons via faults that breach this seal. However, there is also the possibility of an oil charge from source rocks within the Eromanga Basin section. The Jurassic Poolowanna Formation, for example, is known to contain mature, oil-prone source rocks in a substantial kitchen area lying immediately to the northwest of ATP 1194PA. Oil generated from these source rocks in this area may have migrated across the permit area, potentially charging any traps that may be developed within the Eromanga Basin section.
(e) Unconventional reservoirs
A number of Toolachee and/or Patchawarra gas-condensate discoveries have been made in close proximity to ATP 1194PA. These wells often also exhibit good gas shows in poorer quality Permian reservoir sands that were either not tested or flowed on test at non-commercial rates. A number of other exploration wells drilled adjacent to ATP 1194PA that were plugged and abandoned also encountered good gas shows in poorer quality reservoir sands that were either not tested or flowed on test at non-commercial rates. Queensland Oil believes the results of these wells to be indicative of a potential continuous gas play in the northwest part of ATP 1194PA and plans to confirm this interpretation by drilling at least one exploration well in ATP 1194PA to test this concept.
(f) Prospects and Leads
Queensland Oil proposes to pursue oil and gas plays within both the Cooper and Eromanga Basins in ATP 1194PA. These plays include a tight oil and gas play that is present in this area in the Permian Toolachee and Patchawarra Formations of the Cooper Basin, the Late Permian Toolachee oil play (as encountered in the Byrock wells), and oil plays within the Jurassic to Early Cretaceous Eromanga Basin section.
Queensland Oil’s exploration strategy for ATP 1194PA will focus initially on the Permian oil and gas plays. The Company has identified a potential basin-centred gas play in the northwest of the permit area and considers the Permian section in the Cumbroo anticline to warrant further evaluation. A number of structural leads have been mapped at Eromanga Basin level, however, all require the acquisition of further seismic control as a necessary precursor to any exploration drilling.
(g) Permit
Queensland Oil Pty Limited, a wholly owned subsidiary of Real Energy Corporation Limited, was appointed preferred tenderer for the 2014 gazettal block 2014-1-4, now known as ATP 1194PA. Real Energy/Queensland Oil is currently proceeding through the process of negotiating a Native Title agreement with the traditional owners, the execution of which is a requirement for the grant of an Authority to Prospect (ATP 1194P).